Sound recording device



July 8, 1941 A. STPELFELDT 2,248,790

SOUND RECORDING` DEVICE Filed Oct. 6, 1939 Patented July 8, 1941 SOUNDRECORDING DEVICE Arnold Stapelfeldt, Kleln-Machnow, Germany,

assgnor to C. Lorenz Aktiengesellschaft, Berlin-Tempelhof, Germany, acompany Application October 6, 1939, Serial No. 298,212 In GermanyOctober 6, 1938 9 Claims.

The invention relates to magnetic sound recording devices of the kindhaving van interchangeable housing for the drums or reels arranged tocoil and uncoil a wire-shaped record carrier. More particularly, theinvention is concerned with those recording devices whose talking headis arranged to reciprocate under the,

control of a cam disc in accordance with the transverse movements of therecord carrier, that is, movements directed axially with respect to thedrums.

The invention aims to prevent the record carrier from breaking Wheneverthe drum housing is replaced by another. According to the invention thishousing can only be removed When the talking head is in a predeterminedposition, such as the lowest one, for instance. Such predeterminedposition coincides With the position of thel I is secured in position byspring actuated pawls 4. In order to remove the housing I the pawls 4must be moved in the direction of the arrows. Normally, this movement isprevented by stop levers 5 which are fastened on a shaft 6. The talkinghead 'I is made in two parts which may be separated for the purpose ofinserting or removing the recording wire therefrom in a manner known inthe art, for example, similar to that shown in Patent 2,048,487, July21, 1936, to Semi Begun, and has two levers 8 fulcrumed one to each partcarrying a sleeve 9 which when the talking head is in its lowermostposition bears against a lever I0 rigidly mounted on shaft 6. By openingthe talking head as indicated by the arrows the sleeve 9 is moved stillfarther downward and thereby turns the shaft 6 by means of lever I0until the levers 5 are out of engagement with the pawls 4, as shown indotted lines in Fig. 3. The pawls 4 may then be pushed aside, whereuponthe assembly I, 2, 3 may be removed. The pawls 4 thus cannot beretracted from housing I until the talking head is in its lowermostposition and until it has been opened. An advantage of this arrangementalso is that the drum housing cannot be removed without opening thetalking head, since otherwise the record carrier would be destroyed.

According to another feature of the invention a key 20 may be arrangedfor closing the circuit of the motor 2I and an auxiliary contact 22 maybe arranged to interrupt this circuit, such break contact being actuatedby the talking head as soon as this reaches its lowest position asindicated by the dotted line. 'I'he arrangement here is preferably suchthat by operating this key the motor be caused to run forward in orderthat after interchanging the drum housing a record carrier which justreceived a record may be used for making a second record Without therisk of superimposing two records. Such key, which preferably is made inthe form of a push button, in the rst place acts to close a circuitwhich extends from the plus pole of a battery over said key, saidauxiliary contact, through the motor, to the minus pole of the battery.

Numeral I2 denotes the gearing that comprises a cam disc and by whichthe talking head is given its reciprocatory movement.

What is claimed is:

1. In a sound recording device having a record carrier, drums forcoiling and uncoiling this record carrier, a removable housing for thesedrums, a talking head, and drive means for giving the talking head areciprocatory movement axially with respect to said drums, a lockingdevice for securing the said housing in position, and

blocking means controlled by said talking head to prevent such lockingdevice from being released until the talking head is in a predeterminedaxial position.

2. A sound recording device according to claim 1, in which the saidpredetermined positionof the talking head is the lowest positionthereof.

3. A sound recording device according to claim 1, in which said talkinghead is made in two parts which may be opened, and means operative uponopening of said talking head for releasing said means for preventing therelease of said locking device.

4. A sound recording device according to claim 1, wherein said lockingdevice comprises pawls and means -to release said pawls, furthercomprising means being adapted to be operated by the talking head in itslowermost position for operating said releasing means.

5. A sound recording device according to claim 1, in which said talkinghead is made in two parts which may be opened, and the said lockingdevice comprises pawls and stop levers for said pawls and means formoving said stop lever .to

release said pawls on opening the talking head.

6. A sound recording device according to claim 1, having leversfulcrumed to the talking head, a sleeve carried by these levers, andmeans adapted to be acted upon by such sleeve and thereby to releasesaid locking device.

'1. A sound recording device according to claim 1, having a key, anelectric circuit under the control 'of this key,l a. motor included inthis circuit and adapted to drive the said means for producing thereciprocatory movement of the talking head, and means to interrupt suchcircuit lby the talking head reaching its lowest position.

8. A sound recording device according to claim 1, having a key, anelectric circuit under the control of this key. a motor included in thiscircuit and adapted to drive the said means for producing thereciprocatory movement of the talking head, and a break contact in suchcircuit, this contact being under the control of the talking head withthe lowest position thereof.

9. A sound recording device according to claim 1, having a key, anelectric circuit under the control of this key, a. motor included inthis circuit and adapted to drive the said means for originating thereciprocatory movement of the talking head, and means to interrupt suchcircuit by the talking head reaching its lowest position, said key beingadapted to cause the forward motion of the motor.

' ARNOLD STAPELFELDT.

